assembly interruption a dangerous thing

Dear List,

From time to time a pilot is broken or totalled because assembly was
in some way incomplete. I'm simply writing to remind us all not to
permit ourselves to be involved in conversation, however well-
intended, during assembly.

This is motivated by the fact that I discovered that the wing root
tape IS sufficient to hold the right wing onto a Ventus when the main
spar pin is not fully engaged. This discovery was sufficiently
humiliating that I have waited for a few days to confess.

The hookups of the Ventus are brain-dead simple and foolproof, except
that the locking pins really do need to be engaged.

Sometimes I have forgotten to pull off the wing-root tape before
trying to remove the wings during disassembly, which has sparked one
of those random fantastical thoughts, "I wonder if the main spar pin
is really needed."

I normally assemble completely alone; one day last week a friend came
along to see the glider and wanted to 'help' assemble, and of course
happens to be one of those wonderfully friendly, fascinating, chatty
types.

During the latter part of the subsequent 2-hour flight, I heard a
faint low rumble from behind, making me wonder if the engine
compartment doors had fully closed.

After I landed, I discovered that the tape over the right wing root
gap was still fully covering the gap, but the gap had widened from the
usual 2mm to about 5 mm. I need hardly tell you the sense of fright
and self-abasement this inspired.

I immediately realized that I had failed to push the main spar pin
'home' - normally the sequence is to put it halfway through (into the
left spar) to hold the left wing in place while the right wing is
installed, then go straightaway and push it home. In this case an
interruption to correct wing-taping being done by my 'assistant'
caused this step to be skipped.

I recall an old suggestion that pilots should wear a red cap as a
signal not to be interrupted. But the signal won't be obeyed until
it's learned. Maybe a more effective device would be to screen-print
words on the front and back of a light vest to be worn during
assembly, perhaps
"DEAF" - or
"Shut up (please)"

But of course the real discipline is with us assemblers, to not permit
interruptions, and to say to the first person who offers to help,
"Yes, you can help by preventing anyone from talking to me until this
is done."

Dan Johnson

On May 22, 10:43*am, danlj wrote:
Dear List,

From time to time a pilot is broken or totalled because assembly was
in some way incomplete. I'm simply writing to remind us all not to
permit ourselves to be involved in conversation, however well-
intended, during assembly.

This is motivated by the fact that I discovered that the wing root
tape IS sufficient to hold the right wing onto a Ventus when the main
spar pin is not fully engaged. This discovery was sufficiently
humiliating that I have waited for a few days to confess.

The hookups of the Ventus are brain-dead simple and foolproof, except
that the locking pins really do need to be engaged.

Sometimes I have forgotten to pull off the wing-root tape before
trying to remove the wings during disassembly, which has sparked one
of those random fantastical thoughts, "I wonder if the main spar pin
is really needed."

I normally assemble completely alone; one day last week a friend came
along to see the glider and wanted to 'help' assemble, and of course
happens to be one of those wonderfully friendly, fascinating, chatty
types.

During the latter part of the subsequent 2-hour flight, I heard a
faint low rumble from behind, making me wonder if the engine
compartment doors had fully closed.

After I landed, I discovered that the tape over the right wing root
gap was still fully covering the gap, but the gap had widened from the
usual 2mm to about 5 mm. I need hardly tell you the sense of fright
and self-abasement this inspired.

I immediately realized that I had failed to push the main spar pin
'home' - normally the sequence is to put it halfway through (into the
left spar) to hold the left wing in place while the right wing is
installed, then go straightaway and push it home. In this case an
interruption to correct wing-taping being done by my 'assistant'
caused this step to be skipped.

I recall an old suggestion that pilots should wear a red cap as a
signal not to be interrupted. But the signal won't be obeyed until
it's learned. Maybe a more effective device would be to screen-print
words on the front and back of a light vest to be worn during
assembly, perhaps
*"DEAF" - or
"Shut up (please)"

But of course the real discipline is with us assemblers, to not permit
interruptions, and to say to the first person who offers to help,
"Yes, you can help by preventing anyone from talking to me until this
is done."

Dan Johnson

Thanks for posting that, Dan.
I have on more than one occaision, been interrupted during assembly,
and forgoten things. Fortunately for me, nothing that would be likely
to kill me......yet.

Dan,

Yikes! thank you for sharing your scary lesson with your soaring
friends, and we're all very glad you're still around to tell it!

At many soaring clubs, mine included the set up area is a busy and
fairly social hot spot not to mention a magnet for visitors; obviously
a potential assembly check list distraction. Balancing life safety
assembly issues with a clubs PR need be engaging vs. aloof with
visitors and friends alike is a delicate dance. I've thought of
perhaps placing/hanging a polite but obvious laminated sign perhaps in
Red on my open trailer or on the canopy or between the canopy and
glare shield during assembly that simply states something like:

"CRITICAL AIRCRAFT ASSEMBLY IN PROGRESS
Please do not disturb the pilot until this sign is removed.
Thank you, Name and glider ID"

That simple addition to the assembly process just may save a life
someday, maybe mine!

Rick - 21

What about encouraging pilots doing assembly to wear brightly colored
ear muffs or ear plugs to both discourage interactions and remove
distractions?

On May 22, 11:50 am, Rick Culbertson wrote:
Dan,

Yikes! thank you for sharing your scary lesson with your soaring
friends, and we're all very glad you're still around to tell it!

At many soaring clubs, mine included the set up area is a busy and
fairly social hot spot not to mention a magnet for visitors; obviously
a potential assembly check list distraction. Balancing life safety
assembly issues with a clubs PR need be engaging vs. aloof with
visitors and friends alike is a delicate dance. I've thought of
perhaps placing/hanging a polite but obvious laminated sign perhaps in
Red on my open trailer or on the canopy or between the canopy and
glare shield during assembly that simply states something like:

"CRITICAL AIRCRAFT ASSEMBLY IN PROGRESS
Please do not disturb the pilot until this sign is removed.
Thank you, Name and glider ID"

That simple addition to the assembly process just may save a life
someday, maybe mine!

Rick - 21

Dan,

That scares me, and I'm fearless!

Wayne
HP-14 "Six Foxtrot"
http://www.soaridaho.com/


"danlj" wrote in message
...
Dear List,

From time to time a pilot is broken or totalled because assembly was
in some way incomplete. I'm simply writing to remind us all not to
permit ourselves to be involved in conversation, however well-
intended, during assembly.

This is motivated by the fact that I discovered that the wing root
tape IS sufficient to hold the right wing onto a Ventus when the main
spar pin is not fully engaged. This discovery was sufficiently
humiliating that I have waited for a few days to confess.

The hookups of the Ventus are brain-dead simple and foolproof, except
that the locking pins really do need to be engaged.

Sometimes I have forgotten to pull off the wing-root tape before
trying to remove the wings during disassembly, which has sparked one
of those random fantastical thoughts, "I wonder if the main spar pin
is really needed."

I normally assemble completely alone; one day last week a friend came
along to see the glider and wanted to 'help' assemble, and of course
happens to be one of those wonderfully friendly, fascinating, chatty
types.

During the latter part of the subsequent 2-hour flight, I heard a
faint low rumble from behind, making me wonder if the engine
compartment doors had fully closed.

After I landed, I discovered that the tape over the right wing root
gap was still fully covering the gap, but the gap had widened from the
usual 2mm to about 5 mm. I need hardly tell you the sense of fright
and self-abasement this inspired.

I immediately realized that I had failed to push the main spar pin
'home' - normally the sequence is to put it halfway through (into the
left spar) to hold the left wing in place while the right wing is
installed, then go straightaway and push it home. In this case an
interruption to correct wing-taping being done by my 'assistant'
caused this step to be skipped.

I recall an old suggestion that pilots should wear a red cap as a
signal not to be interrupted. But the signal won't be obeyed until
it's learned. Maybe a more effective device would be to screen-print
words on the front and back of a light vest to be worn during
assembly, perhaps
"DEAF" - or
"Shut up (please)"

But of course the real discipline is with us assemblers, to not permit
interruptions, and to say to the first person who offers to help,
"Yes, you can help by preventing anyone from talking to me until this
is done."

Dan Johnson

Dan,
Thanks for posting that, but the truth is, interuptions WILL occur.
Suppose someone crashed right in front of you while you were
assembling? Don't tell me you won't be interupted. The answer lies in
a final critical assembly check which includes not only the flight
controls but the main wing pins and TE probe. BTW, your Ventus wing
won't stay on with just wing tape, that pin forms the second member
and must have been into the second spar far enough to take the flight
loads. You're one lucky guy!

JJ, who has twice failed to connect the outboard ailerons on an ASH-25
because I was explaining how I never forget to hook everything up to
an on-looker! But, I caught it both times when I did my critical
assembly check.

On May 22, 1:16*pm, JJ Sinclair wrote:
BTW, your Ventus wing
won't stay on with just wing tape, that pin forms the second member
and must have been into the second spar far enough to take the flight
loads.

I initially thought the wing pin on a Ventus, like other gliders that
engage a spar end pin in the opposite root, takes no flight loads.

I can see though that any yawing would tend to push the wings apart as
the fuselage would tend to rotate between the wing roots just as if
the lift pins are not properly shimmed. I can see that would quite
quickly cause the tape to yield.

So I agree that, althought the wing pin carries no lift load when the
wings are fully engaged it probably does carry flight loads due to
yawing.

Maybe the OP flys very smooth and co-ordinated? Maybe he's just very
lucky.

Andy

Hallo JJ Sinclair, you wrote at 22.05.2008 22:16

Dan,
Thanks for posting that, but the truth is, interuptions WILL occur.
Suppose someone crashed right in front of you while you were
assembling? Don't tell me you won't be interupted. The answer lies in
a final critical assembly check which includes not only the flight
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
!

That's it.

regards
Werner

Create a rigging check list if it helps - when I rig I also get someone to
independantly check its rigged correctly- a very good habit to get into
especially if you don't have auto control connections.

Chris

Agree with JJ. Part of the final checklist should include visually
verifying safetied wing pins. That pretty much tells you they are in
the right place and not going anywhere.